Conveyor tensioning assembly

Abstract

A conveyor tensioning assembly for an article conveyor is mounted to the frame of the article conveyor, and connected to a take-up sprocket. The conveyor tensioning assembly includes a movable rack that is engaged and moved by an advancing gear of an advancing and holding assembly in a first direction, causing the take-up sprocket of the article conveyor to be urged outwardly against the conveyor chain of the article conveyor so as to take-up any slack existing within the conveyor chain and place the conveyor chain under tension. Once the conveyor chain has been tensioned, the rack is engaged by a holding gear mounted on a one-way clutch, which prevents the holding gear from rotating in a counter-clockwise direction. The holding gear retards in any rearward movement of the rack so as to resist slippage and/or backlash of the rack to prevent the chain from losing tension and slack being formed therein to maintain the conveyor chain under a substantially constant tension.

Wherefore, the following is claimed: 
     
       1. A tensioning assembly for an article conveyor having a conveyor chain passing about a series of sprockets, said tensioning assembly comprising: a rack;   means for moving said rack in a first direction, said means for moving said rack being positioned adjacent the rack and including a cylinder assembly mounted adjacent said rack and an advancing member connected to said cylinder assembly and engaging said rack so that as said cylinder assembly moves said advancing member in said first direction said advancing member urges said rack in said first direction:   said advancing member including an advancing gear mounted on a one-way clutch so as to be rotatable in one direction while resisting rotation in an opposite direction;   a carrier mounted to a first end of said rack so as to move with said rack and having a take-up sprocket attached thereto for the conveyor chain such that said take-up sprocket is moved with the movement of said rack to take up slack from the conveyor chain; and   holding means mounted along said rack adjacent said means for moving and having a one-way clutch, said holding means adapted to engage said rack and enable said rack to move in said first direction to remove slack from the conveyor chain while retarding movement of said rack in an opposite direction to prevent backlash and slippage of the conveyor chain.   
     
     
       2. The tensioning assembly of claim 1, said cylinder assembly further including a pair of pneumatic cylinders. 
     
     
       3. The tensioning assembly of claim 1 and further comprising a sensor positioned along said rack adjacent said means for moving said rack for detecting a second end of said rack indicating stretch of the conveyor chain. 
     
     
       4. The tensioning assembly of claim 1 and further comprising a support slide mounted above said carrier and along which said carrier is supported and moves to move said take-up sprocket outwardly to a tensioning position. 
     
     
       5. The tensioning assembly of claim 1 and wherein said holding means comprises a holding gear mounted on a one-way clutch so as to be rotatable in one direction while being held against rotation in an opposite direction, said holding gear rotatably engaging said rack to enable movement of said rack in said first direction while resisting movement of said rack in said opposite direction to prevent slipping of the conveyor chain and the forming of slack in the conveyor chain. 
     
     
       6. In an article conveyor system of the type having a frame, a series of sprockets mounted about the frame and a conveyor chain extended about the sprockets and rotated along a conveying path, the improvement therein comprising: a movable rack mounted to the system frame and connected to a take-up sprocket for the conveyor chain for moving said take-up sprocket outwardly to tension the conveyor chain;   means for moving said rack in a first direction for moving said take-up sprocket to a tensioning position to enable adjustment of the tension in the conveyor chain, said means for moving said rack including a cylinder assembly mounted adjacent said rack and an advancing member connected to said cylinder assembly and engaging said rack so that as said cylinder assembly moves said advancing member in said first direction, said advancing member urges said rack in said first direction;   said advancing member including an advancing gear mounted on a one-way clutch so as to be rotatable in one direction while resisting rotation in an opposite direction; and   means for securing said rack against movement in a second direction opposite said first direction, said means for securing being positioned along and in engagement with said rack, said means for securing including a clutch constructed and arranged to resist movement of said rack in said second direction while permitting movement of said rack in said first direction to retard backlash of said rack and maintain the conveyor chain under tension.   
     
     
       7. The system of claim 6 and wherein said clutch comprises a holding gear mounted on a one-way clutch so as to rotate in one direction while being held against rotation in an opposite direction, said holding gear rotatably engaging said rack to enable movement of said rack in said first direction while resisting movement of said rack in said second direction to prevent slipping of the conveyor chain and the forming of slack in the conveyor chain. 
     
     
       8. The system of claim 6 and further including a release means for disengaging both said means for moving said rack and said clutch from said rack to enable said rack to be moved in said second direction to a retracted position. 
     
     
       9. The system of claim 6 and wherein said advancing member further includes a slide plate to which said advancing gear is mounted, said slide plate being mounted to said cylinder assembly so as to be movable in said first and said second directions by said cylinder assembly. 
     
     
       10. The system of claim 6 and further including a series of sensors mounted at spaced intervals along said rack for detecting said rack at varying positions to provide varying amounts of tension in said conveyor chain. 
     
     
       11. In an article conveyor system of the type having a frame, a series of sprockets mounted about the frame and a conveyor chain extended about the sprockets and rotated along a conveying path, the improvement therein comprising: a movable rack mounted to the system frame and connected to a take-up sprocket for the conveyor chain for moving said take-up sprocket outwardly to tension the conveyor chain:   means for moving said rack in a first direction for moving said take-up sprocket to a tensioning position to enable adjustment of the tension in the conveyor chain;   means for securing said rack against movement in a second direction opposite said first direction, said means for securing being positioned along and in engagement with said rack and including a clutch constructed and arranged to resist movement of said rack in said second direction while permitting movement of said rack in said first direction to retard backlash of said rack and maintain the conveyor chain under tension; and   a sensor positioned along said rack in a position for detecting a second end of said rack indicating tensioning of the conveyor chain.   
     
     
       12. A method of tensioning a conveyor chain to remove slack therefrom, said method comprising the steps of: actuating a cylinder assembly;   engaging and moving a rack in a first direction with an advancing member so as to move a take-up sprocket outwardly;   tensioning the conveyor chain until the tension in the chain substantially balances the force of the cylinder assembly moving the take-up sprocket outwardly; and   providing an advancing gear mounted on a one-way clutch rotatable in said first direction only, and rotating said advancing gear on said rack as said rack is moved in said first direction so as to enable the rack to move in said first direction while resisting movement of the rack in an opposite direction once the conveyor chain has been tensioned to prevent backlash of the rack and the forming of slack therein.   
     
     
       13. A method of tensioning a conveyor chain to remove slack therefrom, said method comprising the steps of: actuating a cylinder assembly;   engaging and moving a rack in a first direction with an advancing member so as to move a take-up sprocket outwardly by moving an advancing gear in said first direction in response to the actuation of the cylinder assembly, said advancing gear engaging and urging the rack in said first direction;   tensioning the conveyor chain until the tension in the chain substantially balances the force of the cylinder assembly moving the take-up sprocket outwardly; and   providing a clutch means that engages and rotates as the rack is moved in said first direction to enable the rack to move in said first direction while resisting movement of the rack in an opposite direction once the conveyor chain has been tensioned to prevent backlash of the rack and the forming of slack therein.   
     
     
       14. The method of claim 13 and wherein the step of actuating said cylinder assembly includes the step of pulsing an air cylinder for a desired time. 
     
     
       15. The method of claim 13 and further including the steps of disengaging the clutch means from the rack and moving the rack in a second direction to reset the rack to an initial retracted position in response thereto.